Error 6... Please help!

I have this iPhone 3G and I am trying to restore it because every time I plug it in to itunes it tells me its in recovery mode and needs to restore. I tried restoring it and it when through the whole process at the end it gave me an error 6. This is with 4.2.1. When I do a normal restore it gives me an error 9. Any ideas?

Edit: Also, I dont know what was done to the iphone before i got it. I got it without a screen or anything. Jus tthe motherboard, the charging dock, and the battery.